High recovery condenser



Aug. 29, 1967 P, c. HOLDEN 3,338,052

HIGH RECOVERY CONDENSER Filed Oct. 22, 1965 v 5 Sheets-Sheet l PRESSURE1 LENGTH ALONG TURBINE AXIS g3 |NvENToR Poul C. Holden Aug- 29, 1967 P.c. HOLDEN 3,338,052

HIGH RECOVERY CONDENSER Filed Oct. 22, 1965 .3 Sheets-Sheet 2 Aug. 29,1967 P. c. HOLDEN HIGH RECOVERY CONDENSER 5' Shee ts-Sheet Filed Oct.22, 1965 United States Patent O 3,338,052 HIGH RECOVERY CONDENSER PaulC. Holden, Newtown Square, Pa., assignor to Westinghouse ElectricCorporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Oct.22, 1965, Ser. No. 502,187 Claims. (Cl. 60-95) This invention relates toapparatus for condensing vapor, more particularly to vapor condensingapparatus of the surface type, and has for an object to provide improvedapparatus of this type.

One of the main objects of this invention is to provide a surface typevapor condenser in which vapor admitted at high velocity forcondensation is rapidly yet effectively reduced in velocity to promotecondensation of the vapor by heat exchange in a more eiiicient mannerthan heretofore.

Another object is to provide a vapor condenser of the above type inwhich high velocity vapor admitted thereto for condensation ispreliminarily' rapidly dilused in a steam lane and in which the boundarylayer flow formed during diiiusion is continuously removed from thevapor lane by entrainment with the vapor as it ows into the tube fieldfor condensation.

It has been found from tests of double opposed-dow steam turbine modelsthat the pattern of the steam flow leaving the turbine exhaust hood andentering the steam condenser has large ow concentrations at the ends ofthe turbine. This phenomenon produces high velocity cores having a totalpressure substantially higher than the nominal condenser pressure andspaced from each other by a lowertotal pressure region. Accordingly,much of the velocity energy of the cores is dissipated in large eddiesformed in the lower pressure region with attendant undesirable increasein the average pressure level of the entire condenser. As wellunderstood in the art, this effect increases the heat rejection to theheat sink and reduces the power output of the turbine.

In accordance with the invention, there is provided an arrangement forrecovering the high velocity energy of the above steam flow cores,thereby to reduce the average operating pressure level of the condenser.

Briefiy, there is 'provided a surface condenser in which at least theupstream peripheral portion of the tube ield is arranged t-o provide avapor lane for the incoming vapor lto be condensed that is of divergentshape, i.e., of increasing cross-sectional area in the direction of flowof the vapor. Accordingly, as the initially high velocity vapor flowsthrough the vapor lane, at least a portion of the high velocity head isconverted to pressure with attendant low velocity by diffusion whichassures that subsequent turning losses of the vapor, as it is drawn intothe tube field for condensation, are minimized.

To facilitate the formation of the divergent vapor lane portion, thetubes are disposed normal to the axis of rotation of the turbine withwhich the condenser is employed, and where the turbine is of the doubleopposedow type with axially spaced exhaust hoods, the axially opposedperipheral portions of the condenser tube eld are symmetrically arrangedto form a diffusing vapor lane for each of the vapor ow streams from theturbine exhausts.

A high rate of diffusion is eiciently and readily attained with theinvention by spacing the tubes with relation to each other, therebyforming spaces in communication with the vapor lane, which spaces areeffective to withdraw the relatively slow moving boundary layer vaporbefore appreciable accumulation.

The above and other objects, are effected by the invention as will beapparent from the following descrip- ICC tion and -claims taken inconnection with the accompanying drawings, forming a part of thisapplication, in which: FIGURE 1 is a diagrammatic longitudinal sectionalview of a double opposed-flow condensing steam turbine, illustratingtypical exhaust steam flow conditions;

FIG. 2 is a chart comparing the exhaust steam pressure distributionattained with the invention and With l the turbine arrangement shown inFIG. l;

FIG. 3 is a longitudinal sectional view of a steam condenser formed inaccordance with the invention;

FIG. 4 is a transverse sectional view taken on line IV-IV of FIG. 3; and

FIG. 5 is a view similar to FIG. 4, modification of the invention.

Referring to the dra-wings in detail, in FIG. 1 there is shown in highlydiagrammatic form, a condensing steam turbine 10 of the well-knowndouble opposed-How type comprising identical left and right-hand steamexpansion sections 11 and 12 carried by a shaft 13 comm-on to bothexpansion sections, and disposed within a common shell structure 14. Theshell 14 is provided with the usual centrally disposed steam inlet 15and a pair of Iaxially opposed exhaust hoods 16 and 17 having downwardlyextending steam outlets 18 and 19.

The outlets 18 and 19 are provided with an external peripheral flange 20that is attached to the inlet neck portion 21 of a conventional surfacecondenser (not shown) so that, in operation, steam admitted to theturbine through the inlet 1S liows to the left through the expansionsection 11 and to the right through the expansion section 12 and isexhausted from the turbine hoods 16 and 17 in two axially spaced anddownwardly directed streams through the outlets 18 and 19 into thecommon condenser neck portion 21, as indicated by the arrows 23 and 24.

The two exhaust steam streams 23 and 24 are substantially identical andform cores 18a and 19a of high velocity in the axially opposed endregions 25 and 26 of the condenser neck portion.

If the high velocity cores 18a and 19a are permitted to diffuse in thecondenser neck portion, much of the velocity energy present in the coresWill be dissipated in large eddies 28 and 29 formed in the low velocityregion 30 of the neck portion intermediate the end regions 25 and 26.

The above conditions are indicated graphically in the chart shown inFIG. 2, wherein there is shown a typical total pressure distributioncurve 31 having high absolute pressure portions 32 and 33 correspondingto the end regions 25 and 26 and a substantially lower absolute pressurecentral portion 34 corresponding to the intermediate region 30. It willbe noted that the central curve portion 34 lies adjacent a dottedhorizontal pressure line 35 indicating static pressure, while the endcurve portions 32 and 33 lie considerably above the static pressure line35. Accordingly, the portions of the curve 31 above the static pressureline (portions 32 and 33) indicate the velocity components of the cores18a and 19a, since total pressure as well understood in the art is asummation of static pressure and dynamic pressure and dynamic pressureis a measure of velocity energy of a fluid.

In accordance with the invention, as best shown in FIGS. 3 and 4, thereis shown a steam turbine 37 of the same type as the turbine 10 describedin conjunction with FIG. l and provided with a surface condenser 38adapted to receive the exhaust steam from the steam turbine, in whichthe losses due to eddie currents 28 and 29 (FIG. 1) are substantiallyminimized and the velocity energy of the high velocity steam cores 18aand 19a is su-bstantially recovered.

The condenser 38 is provided with a bundle or group but illustrating aof closely spaced parallel tubes 39, hereinafter termed a tube field,having their end portions received in a pair of tube sheets 40 and 41and disposed within a shell or housing 42 deiining a chamber 42a. Theupper part of the housing 42 is provided with an exhaust steam inlet orneck portion 43 communicating with the chamber 42a and having aperipheral ange portion 44 attached to a mating flange 45 provided inthe exhaust hood 46 of the steam turbine 37. The exhaust hood 46corresponds to the exhaust hood 17 in FIG. l.

At each end of the condenser 38 there is provided water box structure 48and 49 associated with the tube sheets 40 and 41, respectively, thewater box 48 being the inlet box and having a water inlet 50 and thewater box 49 :being the outlet box and having a water outlet 51.

The tube field 39 is disposed in the chamber 42a and in operation isexternally traversed by steam and internally traversed by coolant waterowing in one pass from left to right, as viewed in FIG. 3, from theinlet box 48 to the outlet box 49. The tube eld 39 is supported atspaced intervals along its length by suitable support plates 52, whichin turn are anchored to the condenser housing 42 by mounting lugs 53.

The central region of the tube iield is devoid of tubes and the supportplates 52 are provided with central openings 54, thereby forming acentral air collection space 55 extending substantially the entirelength of the tube field.

An air offtake pipe 56 extends lengthwise through the air collectionspace and is provided with a plurality of apertures 57 communicatingwith the space. This pipe is extended through one of the water boxes,for example the inlet box 48, and is connected to a suitable source ofsuction (not shown).

The lower portion of the condenser housing 42 is provided with adepending well portion 58 communicating with the chamber 42a forcollecting the condensate, and a condensate outlet 59 is provided forremoving the condensate from the condenser.

As thus far described the condenser is substantially conventional. Inaccordance with the aspects of the invention, the tube field 39 isarranged to extend in a direction normal to the axis .of rotation R ofthe turbine 37, as shown in FIG. 3, and the condenser neck portion 43 isflared downwardly and outwardly to provide a distribution region 60 forthe exhaust steam from the turbine hood 46.

Y As best shown in FIG. 4, the tube field 39 is of smallercross-sectional area than that of the condenser housing and is disposedin a central position therein. The tube iield 39 is symmetrical withrespect to its vertical axis and jointly with the side walls 62 and 63ofthe condenser housing forms a pair of vertically extending steam lanes64 and 65 communicating with the steam distribution region 60.

The right-hand steam lane 65 is bounded and thus dened on the left bythe tubes 66 disposed in the outer periphery of the tube field 39. Theperiphery of the tube iield defining the left side of the right-handlane 65 is arranged to provide a divergent portion 67 adjacent the inlet68, at the upstream end of the lane with respect to direction of steamflow, and, preferably though not essentially a convergent dowstreamportion 69.

The left-hand lane 64 is similar to the right-hand lane 65 and need notbe further described.

In operation, steam exhausted from the turbine hood 46 ows downwardlythrough the condenser neck portion 43 into theV distribution region 60with a high velocity steam core, indicated by the arrows 72, directed tothe R.H. steam lane 65. As the high velocity steam core72 ows throughthe divergent lane portion 67, it undergoes rapid initial diiiusion withattendant substantial conversion of velocity to pressure. That is, thevelocity head is reduced and the static pressure is correspondinglyincreased without substantial loss of energy.

The rate of divergence of the divergent portion 67 may be considerablygreater than that of ordinary ditfusers without encountering boundarylayer separation. This is feasible, since the spaces between the tubes66 form suction passages connecting the steam lane with the aircollection space 5S at the center of the tube field, which space 55 ismaintained at reduced pressure by the air oiitake pipe 56. Accordingly,as the steam velocity is reduced during its flow through the divergentlane portion 67, it more readily turns to the left through the spacesbetween the tubes 66 to undergo heat exchange with the tubes and thusthe turning losses due such ow are minimized. l u

At the same time as the steam is directed from the lane and condensed,and the incondensible gases, such as air are removed from the condenserby the oitake pipe 56, the mass ow of the remaining steam owing throughthe lower lane portion 69 is progressively diminished. Hence, the lowerlane portion 69 may ybe made somewhat convergent without loss in flowefficiency, thereby permitting a greater number of tubes to be providedin the tube field and increasing the condensing capacity of thecondenser without increasing the size of the condenser.

The L.H. lane 64 (FIG. 4) operates in the same manner as the R.H. lane65, described above and is effective to diifuse the high velocity stea-mcores, indicated by arrows 74, exhausted from the turbine exhaust hood(not shown) disposed at the other end of the turbine 37 andcorresponding to the exhaust hood 16 in FIG. l.

Referring to FIG. 2 again, there is shown a curve 31a, similar to thecurve 31 described in conjunction with a prior arrangement, but showingthe improved pressure distribution characteristics in the condenser neckportion 43 attained with the invention. The curve 31a has high totalpressure end portions 32a and 33a and a low total pressure intermediateportion 34a, corresponding, respectively, to portions 32, 33 and 34 ofthe curve 31 but of correspondingly lower pressure value. Also, thestatic pressure value indicated by the dotted line 35a is lower thanthat indicated by the dotted line 35, previously described. The abovephenomenon is attained primarily because of the substantial reduction inlosses due to the eddies 28 and 29 (FIG. 1) and because of the highlyeflicient and deffusion in the divergent portions of the steam lanes 63and 64.

Since the total pressure levels indicated by the curve 31a are lowerthan those indicated by the curve 31, and since the static pressurelevel 35a is lower than that indicated by the dotted line 35, theturbine exhaust pressure (back pressure on the turbine) iscommensurately lower, thereby permitting the steam to undergo greateruseful expansion in the turbine before condensation in the condenser.

FIG. 5 illustrates another embodiment of the invention. In thisembodiment, there is shown a dual condenser 75 comprising two identicaltube fields 76 and 77 disposed in side-by-side relation within a commonhousing 78.

The condenser 75 serves to condense the exhaust of two tandem connectedcondensing turbines 79 and 80 of the double opposed-How type shown inFIG. 1.

The tube fields 76 and 77 are substantially similar in al1 aspects tothe tube field 39 described in conjunction with FIGS. 3 and 4 and aredisposed directly below their associated turbines 79 and 80.

The tubes in the periphery of the tube iield 77 together with theright-hand wall 81 of the housing form a steam lane 82, and, in asimilar manner, the tube field 76 together with the left-hand wall 83form a steam lane 84 similar to the steam lanes 64 and 65, respectively,previously described.

In this embodiment, however, the two tube fields 76 and 77 jointlydefine a -central steam lane 85. The central steam lane 85 is alsoprovided with a divergent inlet portion 86, and a preferably slightlyconvergent downstream portion 87.

This embodiment operates in a manner similar to the first embodiment toreduce steam energy losses due to eddies, i.e., the high velocity steamcores 88 and 89 at the opposite ends of the turbines are-diffused inpassage through the steam lanes 82 and S4, respectively. However, thehigh velocity steam cores 90 and 91 at the adjacent ends of the turbinesare jointly directed to the central lane 85 and diffused in passagetherethrough, in a manner similar to that previously described. Thesteam lane 85 is preferably of larger cross-sectional area than thelanes 82 and 84 to accommodate the greater mass fiow of steam.

It must further be pointed out that each tube field 77 and 76 isprovided with a central air collection space 88 and 89, respectively.Accordingly, as the steam flows through the central lane 85, about 50%is turned into the left tube field 76 for condensation and the other 50%is turned into the right tube field for condensation. Hence, theboundary layer fluid is withdrawn past the tubes in both tube fields.

It will now be seen that the invention provides an arrangement whereinthe high velocity cores of exhaust steam from a turbine of the doubleopposed-flow type are initially and rapidly diffused during flow throughthe steam lanes of a condenser with minimum loss of energy, thereby (l)reducing the back pressure on the turbine, (2) increasing the usefulexpansion availability of the steam through the turbine, and (3)increasing the heat exchange capacity of the condenser.

Although several embodiments of the invention have been shown, it willbe obvious to those skilled in the art that it is not so limited, but issusceptible of various other changes and modifications without departingfrom the spirit thereof.

I claim as my invention:

1. A surface condenser comprising a shell structure defining a chamberand having an inlet opening for admitting vapor to said chamber,

a tube field having a group of elongated tubes disposed in said chamberand in closely spaced relation with each other,

said tube field having a peripheral portion spaced from said shellstructure and jointly therewith dening a vapor flow lane,

said vapor lane having an upstream end portion through which the vaporis directed and said peripheral portion being arranged in a manner todiffuse said vapor with attendant conversion of a portion of thevelocity of said vapor into pressure,

means for directing a coolant fluid through said tubes, whereby in theresulting heat exchange the vapor is condensed, and

means associated with said chamber for collecting the condensate.

2. The structure recited in claim 1 wherein the peripheral portion ofthe tube field and the shell portion jointly impart a divergent shape tothe upstream end portion of said vapor lane,

means is provided for withdrawing incondensible gases from the interiorof the tube field, and

at least a portion of the boundary layer vapor flow in the divergentlane portion is directed towards the interior of the tube field.

3. The structure recited in lclaim 1 wherein the peripheral portion ofthe tube field and the shell portion jointly impart a shape to the vaporlane that is divergent in the direction of the vapor flow,

the tube field has a central portion devoid of tubes and defining aspace,

means is prov-ided for imparting a reduced pressure in said space, and

at least a portion of the boundary layer vapor flow in the divergentlane portion is directed toward said space in a plurality of paths pastthe tubes.

4. In a turbine power plant, comprising a double ow vapor turbine havinga rotational axis and a pair of exhaust outlets for expanded vaporaxially spaced from each other; and

a surface condenser for condensing the expanded vapor from said pair ofoutlets,

said condenser comprising a shell structure defining a chamber having aninlet opening for admitting the vapor to said chamber,

a tube field having a group of elongated tubes disposed in closelyspaced relation with each other in said chamber and extendingsubstantially normal to said rotational axis,

said tube field having at least one peripheral portion spaced from saidshell structure and jointly therewith defining a vapor fiow lane for thevapor flow from one of said exhaust outlets,

said vapor lane having an upstream end portion and a downstream portionextending from said end portion and diverging in downstream direction,whereby the ow of vapor through said vapor lane is initially diffusedwith attendant conversion of at least a portion of the velocity of saidvapor into pressure,

means for directing a coolant fluid through said tubes, whereby in theresulting heat exchange the vapor is condensed,

means for evacuating incondensible gases from the interior of the tubefield,

at least a portion of the boundary layer vapor flow in the divergentlane portion being withdrawn therefrom toward the interior of the tubefield, and

means associated with the downstream portion of said chamber forcollecting the condensate.

5. The structure recited in claim 4, wherein:

the peripheral portion of the tube field defining the vapor lane isprovided with a plurality of spaces by the tubes and the boundary layerfiow is progressively directed through said spaces to promote the vapordiffusion.

6. In a turbine power plant comprising at least two double fiow vaporturbines connected in tandem and having a common rotational axis,

each of said turbines having a pair of axially spaced exhaust outletsfor expanded vapor,

a surface condenser for condensing the expanded vapor from said outletscomprising a shell structure defining a chamber and means for admittingthe vapor to said chamber,

a pair of tube fields in said chamber, each having a group of elongatedtubes disposed in closely spaced relation with each other and extendingnormal to said rotational axis,

said tube fields being disposed in spaced side-by-side relation witheach other and having juxtaposed peripheral portions jointly defining acentral vapor ow lane having a divergent upstream inlet portion, wherebythe flow of vapor through said vapor lane is initially diffused withattendant conversion of at least a portion of the velocity of said vaporinto pressure,

means for directing a coolant uid through said tubes, whereby in theresulting heat exchange the vapor is condensed,

means for evacuating incondensible gases from the interior of said tubefields,

at least a portion of the boundary layer vapor flow in the divergentlane portion being withdrawn therefrom toward the interior of the tubefields, and

means disposed below said tube fields for collecting the condensate.

7. The structure recited in claim 6, wherein the peripheral portions ofthe tube tields defining the vapor lane are provided with a plurality ofspaces by the tubes and the boundary layer flow in said divergingportion is progressively directed through said spaces to promote thevapor diffusion.

8. The structure recited in claim 6, wherein:

the divergent portion of the vapor lane comprises substantially lessthan 50% of the length of the vapor posed-flow vapor turbine of thecondensing type havinga rotational axis and a pair of axially spacedexhaust outlets for expanded vapor,

a surface condenser for condensing the expanded vapor from said pair ofoutlets,

said condensed comprising a shell structure disposed below said turbineand having an upper neck portion defining an inlet opening common tosaid pair of outlets and a pair of side Walls,

a tube field disposed in said chamber having a group of elongated tubesextending substantially normal to said rotational axis,

said tube field being of substantially symmetrical cross section about avertical center line and having a pair of 'opposed outer peripheralportions disposed in spaced relation with the associated said sidewalls,

each of said peripheral tube field portions and associated side wallsjointly defining a downwardly extending vapor lane having an inletcommunicating with an asspciated turbine exhaust outlet and shaped in amanner to diffuse the incoming vapor with attendant conversion of atleast a portion of the vapor velocity into vapor pressure,

means for directing a coolant uid through said tubes thereby to cooland' condense the vapor during flow therepast,

means communicating with the central portion of said tube iield forevacuating incondensible gases separated from the condensing vapor,

at least a portion of the boundary layer in the diffused vapor flowbeing withdrawn from said vapor lane in a progressive manner through thespaces between adjacent tubes toward said central portion, and meansdisposed in the lower portion of said shell for collecting the vaporcondensate'. 10. A surface condenser comprising l a shell structurehaving an inlet opening for exhaust steam to be condensed, a tube fieldin said shell structure disposed below said inlet and substantiallycoextensive therewith, said tube field comprising a bundle of closelyspaced tubes defining ow paths for the steam and having an internalportion devoid of tubes and forming an incondensible gas collectionspace, means for maintaining a reduced pressure in said space, the tubesin the periphery of said tube field at least partially deiining a pairof opposed steam flow lanes communicating with said steam inlet openingand au intermediate steam region between said lanes, said steam flowlanes receiving high velocity steam and being subject to a higher totalpressure than said intermediate region, and the tubes in the peripheryof said tube field defining said steam lanes being arranged in a mannerto impart a divergent shape to said steam lanes thereby to substantiallyconvert a portion of said total pressure to static pressure with minimumloss of energy.

References Cited UNITED STATES PATENTS 7/1924 Lonsdalev 165--114 5/1929Kirgan 165-114

1. A SURFACE CONDENSER COMPRISING A SHELL STRUCTURE DEFINING A CHAMBERAND HAVING AN INLET OPENING FOR ADMITTING VAPOR TO SAID CHAMBER, A TUBEFIELD HAVING A GROUP OF ELONGATED TUBE DISPOSED IN SAID CHAMBER AND INCLOSELY SPACED RELATION WITH EACH OTHER, SAID TUBE FIELD HAVING APERIPHERAL PORTION SPACED FROM SAID SHELL STRUCTURE AND JOINTLYTHEREWITH DEFINING A VAPOR FLOW LANE,